On 16 September 1943 it commission date, it did not have one.
I have a brief look at this and you may be right. I could not find any pictures with the security railings with a date. When I get time I will look into this with more detail. Dougie, may have the answer, at hand.
Nevertheless, this open up another quection. Did the late war Type VII/41 had this security railings? There would be no need for them on the very late war u-boat. I will also check this out.
Good spotting, Karel!